Curve modifier doesn't follow curve in the correct axis
Apply the rotation of your curve (CtrlA)
In Edit mode, right click and Switch Direction so that the normals go from bottom to top
You’ve keyframed the Curve modifier's Deform Axis, not sure why, so maybe delete the keyframe, and find the right axis (which seems to be -X)

Your stalk doesn’t completely follow the curve but it’s because it is not originally completely straight,  it’s already a bit curvy before you give it the Curve modifier